SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee1485badb219c57838afee2e5cd6405030a74b6a3a15457f4dd98755d083589' 
  AND token = 'gzW4WjxMGwc+3EiuKKO+TwCG2971fJD1ABWVSMLsyew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}